【摘要】 以润扬长江公路大桥北汊斜拉桥为研究对象,建立了包含桥梁整体结构、索梁锚固区构件及含表面裂纹焊接细节的多尺度模型,采用子模型法获得了索梁锚固区域中应力集中区和裂纹尖端应力场分布,分析了疲劳裂纹长度对应力强度因子的影响,研究了不同长度的初始裂纹的疲劳寿命和考虑检测信息的疲劳可靠度的更新情况.研究结果表明,采用损伤时变特性尤其是易发生的裂纹信息进行多尺度模型更新,可实现桥梁索梁锚固区域中复杂受力区的局部应力分布和疲劳状态可靠度的更新分析,为含裂纹桥梁结构的疲劳状态评定提供了一种精确分析方法,一定程度上可弥补桥梁健康监测系统无法反映复杂构型局部焊缝区域应力分布规律的不足.更多还原

【Abstract】 A multi-scale analytical model of the Runyang Cable-stayed Bridge was developed.This model includes the macro box-girder model,the microscopic cable-girder anchorage zone model,and the mesoscopic crack model.The distribution of stress in the concentration zone of the anchorage structure and the crack tip was obtained by the sub-model method.The effect of the crack length on the stress intensity factor was investigated.The fatigue life under different initial cracks and fatigue failure probability considering the inspection messages were investigated.The results showthat employing time-varying damage information,especially crack information,to update multi-scale analytical model,can improve the analysis of local stress distribution in complicated stress zone and update fatigue reliability index.It is an effective method to assess fatigue state of bridges with crack.To some extent,it can circumvent the problem that the structural health monitoring system cannot detect stress distribution of the weld zone.更多还原